The present invention relates to the use of mixtures, comprising a total of at least 50% by weight of n-alkanols, selected from n-C24-C34 alkanols, as additive in the processing of thermoplastic polymers.
When thermoplastic polymers are processed, for example via mixing rolls, and in particular via extrusion with the aid of, for example, foil extruders, or single-screw extruders or twin-screw extruders, or planetary mills, various processing aids are added as a function of the polymer to be processed. For example, in the case of polypropylene it is usual to add antiblocking agents. In the case of polyvinyl chloride (PVC) it is usual to add numerous processing aids, in particular one or more lubricants.
The processing aid(s) used must usually satisfy a series of demanding requirements. For example, processing aids are intended not only to ease processing and to be easy to feed. They are also intended not to cause any disadvantageous side-effects in the relevant polymer, an example being plateout. In the case of transparent plastics, haze is an undesired side-effect to be avoided. Finally, processing aids are intended to be capable of easy large-scale production.
U.S. Pat. No. 4,132,691 discloses use of partially oxidized polyethylene wax for the processing of PVC, and specifically as lubricant. Partially oxidized polyethylene wax generally, however, leads to haze in the processed polymer, making the relevant polymer rather unsuitable for uses where transparency is important.